feat: icons in the header and on the Montagem controls

The header's search, account and cart get icons, with the item count on the
cart instead of "Carrinho (N)"; on phones only the icons show. The upload
zone, remove, rotate and mirror buttons used Unicode symbols that look
different, or are missing, depending on the system's fonts; they are now
Lucide icons (ISC licence) drawn inline, so nothing new is loaded and the
CSP is unchanged.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

web/site-config.js

@@ -5,6 +5,18 @@
 
 const $=id=>document.getElementById(id);
 const rs=v=>'R$ '+v.toFixed(2).replace('.',',');
+// Ícones (Lucide, licença ISC) desenhados no próprio HTML: nada a carregar, e a
+// cor vem do texto em volta. Os que ficam no HTML estático são os mesmos.
+const ICONES={
+  busca:'<circle cx="11" cy="11" r="8"/><path d="m21 21-4.3-4.3"/>',
+  conta:'<path d="M19 21v-2a4 4 0 0 0-4-4H9a4 4 0 0 0-4 4v2"/><circle cx="12" cy="7" r="4"/>',
+  sacola:'<path d="M6 2 3 6v14a2 2 0 0 0 2 2h14a2 2 0 0 0 2-2V6l-3-4Z"/><path d="M3 6h18"/><path d="M16 10a4 4 0 0 1-8 0"/>',
+  enviar:'<path d="M21 15v4a2 2 0 0 1-2 2H5a2 2 0 0 1-2-2v-4"/><path d="m17 8-5-5-5 5"/><path d="M12 3v12"/>',
+  girar:'<path d="M21 12a9 9 0 1 1-9-9c2.52 0 4.93 1 6.74 2.74L21 8"/><path d="M21 3v5h-5"/>',
+  espelhar:'<path d="m3 7 5 5-5 5V7"/><path d="m21 7-5 5 5 5V7"/><path d="M12 20v2"/><path d="M12 14v2"/><path d="M12 8v2"/><path d="M12 2v2"/>',
+  fechar:'<path d="M18 6 6 18"/><path d="m6 6 12 12"/>',
+};
+const icone=n=>'<svg class="ic" viewBox="0 0 24 24" aria-hidden="true" focusable="false">'+ICONES[n]+'</svg>';
 const fmt=b=>b<1048576?(b/1024).toFixed(0)+' KB'
   :b<1073741824?(b/1048576).toFixed(1).replace('.',',')+' MB':(b/1073741824).toFixed(1).replace('.',',')+' GB';